The Government doesn’t normally interfere in deals, why would politicians want to this time?

Drugs, money and jobs. As one of Britain's biggest pharmaceutical companies, AstraZeneca (AZ) is considered vital both for the provision of medicines but also the critical research and development of new drugs. For example, AZ is pioneering research for respiratory conditions which the NHS is in need; the fear is that in foreign hands these priorities could change. With an ageing population, plenty argue that Britain’s biggest pharma companies should be protected for the national interest, particularly when Pfizer’s chief aim appears to be to reduce its tax bill rather than boost the company’s R&D. If money is Pfizer’s object, there are concerns that investment plans will change; Pfizer has already refused to guarantee AZ’s planned facility in Cambridge. Moreover, AZ employs 6,700 people in the UK.

Thirty years ago, the Government could block any deal, what changed?

In the 1980s Mrs Thatcher introduced reforms that prevented the state from blocking deals just because it didn’t like the prospective owners. Instead interference was limited to concerns about competition not ultimate ownership. The rules became settled policy throughout the years of privatisation. Tony Blair took them further by removing ministers from the merger control process entirely and handing the powers to regulators.

How did Ministers regain more powers over deals?

The Enterprise Act of 2002 included provision for the Business Secretary to intervene in a merger when he felt “public interest considerations” were at stake. But the public interest was carefully defined and limited to defence companies, in the “interests of national security”, and media groups where a “sufficient plurality of views in newspapers” was deemed vital. These powers invoked in 2007 in BSkyB's bid for 17.9pc of ITV and were threatened again when News Corp tried to take over BSkyB in 2011.

Has the Government managed to stop itself interfering in deals outside the media and defence sectors?

Ministers have generally resisted great pressure to intervene. For example, in 2006 when Spain’s Ferrovial bid for BAA, the owner of Heathrow and Gatwick in 2006, Blair and Brown defended inaction with warnings of the dangers of “economic patriotism”. Spain’s Santander bought Abbey National, Corus was snapped up by India’s Tata Steel and Scottish & Newcastle was divided by Carlsberg and Heineken. The financial crisis brought sudden and radical Government intervention. In order to allow Lloyds TSB to buy HBOS at the apex of the crisis in October 2008, the Government forced through an addition to the Enterprise Act which allowed competition rules to be overridden by the “new public consideration ... of the stability of the UK financial system”.

Given all the previous deals, what was all the fuss about Cadbury’s takeover by Kraft?

The public outcry over the sale of Cadbury to Kraft was the biggest display of discontent over a takeover in years. Campaigns on Twitter and Facebook heightened awareness about the fate of the iconic chocolate company and helped spread the cause. Kraft’s turnabout on its pledge not to shut Cadbury’s Somerdale factory, at the cost of 400 jobs, turned the deal into a strong populist cause. Unable to block the deal, the Government commissioned the Kay Review to learn lessons. Labour’s 2010 manifesto included a “Cadbury’s Law” to protect the crown jewels of British industry. But in Government, Vince Cable resisted proposals to introduce protectionist legislation. Instead the Government said it would “engage with companies and their investors ... to promote investment which benefits the UK economy”.

Since AstraZeneca is neither a defence nor media company, nor are there obvious competition or stability issues, what can the Government do this time?

With the spectre of the Cadbury's row looming large over this big and emotive deal, the Government will want to be seen to be more hands-on than usual. There's no agreed proposal yet. David Cameron, David Willetts and Vince Cable are fully involved. John Kingman and Jeremy Heywood have already been appointed to review the impact of the deal. In practice, they will turn to the Takeover Panel provisions. But if these prove insufficient, another change to the Enterprise Act could be introduced – for instance to protect AZ in the interests of long-term public health. The idea is technically possible but fraught with complexities and dangerous precedents about future protectionism.

The IoD says interference would be “disastrous” for British business and trade, is that true?

Britain’s reputation as one of the most liberal economies in the world would be dented. But other big economies are worse. In America big deals are vetted by the Committee on Foreign Investment in the United States for both an economic and national security view. Congress howled in protest when Dubai’s DP World tried to buy six US ports and when China’s CNOOC bid for Unocal. Italy blocked the takeover of Autostrade by Spain’s Abertis. Meanwhile in France, which once declared the yogurt maker Danone a “strategic industry”, Government interference in deals is almost standard.